Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. While often associated with the genital region, the infection can manifest in the mouth, with signs varying by the stage of infection. Understanding these manifestations is important for recognition and timely medical care, as the symptoms progress in a distinct pattern if left untreated.
Oral Transmission and Initial Symptoms
Oral syphilis is most commonly acquired through direct contact with an active sore of an infected individual, primarily during oral sex. The Treponema pallidum bacteria can enter the body through small cuts or abrasions within the mouth or on the lips. Transmission can also occur through kissing if an active lesion is present in the mouth.
Following an incubation period that typically lasts about three to four weeks after exposure, the first sign of infection appears. This initial lesion, known as a chancre, marks the primary stage of syphilis. In the mouth, a chancre can develop on the lips, tongue, gums, or the inner lining of the cheeks.
The oral chancre typically presents as a single, firm, and round sore. A defining characteristic of this primary lesion is that it is usually painless, which can lead to it going unnoticed or being mistaken for a minor irritation.
Despite its painless nature, the chancre is highly infectious as it is teeming with syphilis bacteria. The sore will eventually heal on its own within a few weeks to months, but without treatment, the infection progresses to the next stage.
Progression of Oral Symptoms
If primary syphilis is not treated, the infection advances to the secondary stage, which brings a new set of oral symptoms. This stage typically begins a few months after the initial chancre has healed. One of the characteristic signs of secondary oral syphilis is the appearance of mucous patches. These are flat, oval, grayish-white lesions that can form on the tongue, inner lips, or palate and are also highly contagious.
Another manifestation during the secondary stage can be snail track ulcers, which are linear ulcerations that can appear in the mouth. At the corners of the mouth, moist, raised, gray or white lesions called condylomata lata may develop.
Secondary syphilis often involves a non-itchy skin rash that can cover the body, including the palms and soles, along with flu-like symptoms such as fever, headache, and muscle aches. These symptoms may come and go for months or even years.
Without intervention, the infection can proceed to the tertiary, or late, stage. An oral manifestation of tertiary syphilis is the gumma, which is a soft, tumor-like growth. A gumma is a destructive lesion that can cause significant damage to surrounding tissues, potentially perforating the hard palate or causing deformities of the tongue. Unlike the earlier stages, these lesions are not infectious.
In cases of congenital syphilis, where the infection is passed from a mother to her child during pregnancy or birth, distinct dental abnormalities can occur. These include Hutchinson’s teeth, where the permanent incisors are smaller, more widely spaced, and have notches on their biting surfaces. Another sign is the development of mulberry molars, which have poorly formed cusps and a bumpy surface resembling a mulberry.
Diagnosis and Treatment
A diagnosis of oral syphilis begins with a healthcare provider conducting a physical examination of the sores and taking a detailed health and sexual history. While the appearance of the lesions can be an indicator, definitive diagnosis requires testing to confirm the presence of the Treponema pallidum bacteria.
Confirmation is most commonly achieved through a blood test, such as the rapid plasma reagin (RPR) test, which detects antibodies the body produces to fight the infection. If a chancre is present, a provider may also collect a fluid sample from the sore to examine under a dark-field microscope for the bacteria.
Syphilis is a curable infection treated with antibiotics. Penicillin, given by injection, is the most common treatment for all stages. For individuals with a penicillin allergy, alternative antibiotics are available. Patients must complete the full treatment course, and follow-up blood tests are needed to confirm the infection is cured.
Distinguishing from Other Oral Conditions
Distinguishing oral syphilis from other common mouth conditions based on appearance alone can be challenging. For this reason, a professional evaluation is necessary for an accurate diagnosis.
For instance, cold sores, caused by the herpes simplex virus, present as a cluster of small, painful, fluid-filled blisters. In contrast, a primary syphilis chancre is a single, painless ulcer. The presence of pain is a differentiator.
Aphthous ulcers, commonly known as canker sores, are also painful and appear as small, round ulcers with a white or yellowish center and a distinct red border. They are not sexually transmitted and are not infectious.
Persistent sores in the mouth that do not heal could also be a sign of oral cancer. Cancerous lesions may appear as red or white patches, or as ulcers that may bleed easily. Unlike a syphilis chancre, these lesions persist and may change in size or appearance over time. Any unusual or non-healing sore in the mouth requires a medical diagnosis.